A Unique Engineering Geology Approach to Aid in Design and Construction of a Pipeline Project in Texas

The Tarrant Regional Water District (TRWD) with the City of Dallas Water Utilities (DWU), are currently engaged in the planning, design and implementation of a 350 MGD raw water transmission system, which will run across north central Texas from Lake Palestine to Lake Benbrook. Collectively, the system constitutes approximately 150 miles of 84-inch to 108-inch pipeline and six pump station sites. A geotechnical investigation was conducted along the pipeline alignment and included about 400 geotechnical borings, 150 miles of Electrical Resistivity Tomography (ERT), 100 Cone Penetration Tests (CPT) and geologic mapping. The vast amount of data collected was archived electronically in a geospatial database. Successful pipe design requires communication between IPL program management, the engineering geologist, geotechnical engineer and civil engineer. A unique planprofile was developed to illustrate the vast amount of geologic and geotechnical information collected for the IPL project. The plan-profiles were developed initially from correlation of strata using standard geologic techniques. The profiles were then modified using color codes to illustrate subsurface conditions and areas of geologic concern that are important to the civil engineer for design of the pipeline.